Have been getting the run around all day from BA regarding refund for upcoming flight to Dubai. Planning to send the following to BA. Do I send it to Customer Services by letter (I’ve little faith in them) or do I go to the top and email Sean Doyle?

Ticket bought 03/05.25 for travel ABZ-LHR-DXB return.
Due to fly 06/03/26.
BA website confirms “If you are due to fly between London Heathrow and Abu Dhabi, Amman, Bahrain, Doha, Dubai or Tel Aviv up to and including 15 March you can change your flight date free of charge to travel on or before 29 March. Customers travelling up to and including 8 March may also request a full refund”.
Tried to cancel via MMB however it was not giving full refund and charging £70 fee cancellation for my wife and myself.
Contacted live chat as per enclosed screenshots who advised that my return flight on 14th March was not affected despite pointing out that my outbound flight was on 6th March and fell within the full refund as noted above. Essentially the cancellation was my issue and there would be a £70 charge.
Cancelled my booking via MMB and £130 refund + 100K Avios being refunded. Should be £200 for full refund.
Submitted complaint Ref: XXXXXXXX and later received and email confirming case closed. Refer to enclosed email and case history.